add setting() helper; fix invalid defaults for mysql in table

database/migrations/2017_12_10_014930_create_settings_table.php

@@ -15,11 +15,11 @@ class CreateSettingsTable extends Migration
         Schema::create('settings', function (Blueprint $table) {
             $table->increments('id');
             $table->integer('order')->default(1);
-            $table->string('name')->default('');
+            $table->string('name');
             $table->string('key');
             $table->string('value');
-            $table->string('group')->default('general');
-            $table->text('type')->default('text');
+            $table->string('group')->nullable();
+            $table->text('type')->nullable();
             $table->text('options')->nullable();
             $table->text('description')->nullable();
             $table->timestamps();